GERZEN Wastewater Treatment Plant, Gerzen, Bayern, Germany

The GERZEN wastewater treatment plant is located in Gerzen, a municipality in the Landkreis Landshut district of Bayern, Germany. It served a population of approximately 1,922 people before its closure. The plant was designed with a capacity of 2,800 cubic meters per day and treated an average discharge volume of 481 cubic meters per day, reflecting a utilization rate well below capacity. The plant provided advanced treatment, which goes beyond the secondary treatment required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Advanced treatment typically includes nutrient removal (nitrogen and phosphorus) to protect sensitive water bodies. Although the plant is now closed, its operational history reflects Germany's stringent wastewater standards under national regulations implementing the EU directive. The treated effluent was discharged into a local water body within the Danube River basin. The Danube ultimately flows into the Black Sea, making the plant part of a large transboundary watershed. The region's aquatic ecosystems benefit from advanced treatment, which reduces eutrophication risks and supports biodiversity in downstream rivers and the Black Sea.

The GERZEN plant discharged into a tributary of the Danube River, which flows through southeastern Europe before reaching the Black Sea. The Danube basin supports diverse aquatic life, including migratory fish species such as sturgeon. Advanced treatment at the plant helped minimize nutrient loading, protecting downstream water quality and reducing the risk of algal blooms in the Black Sea.